We hear a lot about “stem cells,” which are front-and-center as a major policy debate in America, one that involves science, medicine, ethics, politics, and much more.
What are the issues? What’s at stake? What are embryonic and non-embryonic stem cells? What are the crucial differences and distinctions we need to make as a society and citizenry?
Stem-cell technologies are some of the newest and fastest developing biotechnologies. Typically, along with genetic engineering and cloning, these technologies constitute the kind of 21st century advances that make this “the century of Biology.”
A stem cell is a type of cell that is nonspecific in its function; in contrast, for instance, to a heart or brain cell, which is functionally specific. There are two major sources of stem cells: embryonic stem cells and non-embryonic stem cells. Embryonic stem cells are obtained from 5- to 12-day old embryos. Although removal of a stem cell from an embryo kills the embryo, the stem cells are valued for their potential to produce any type of cell. That is, they have high plasticity. Conversely, non-embryonic stem cells are found in large quantities in placenta, umbilical cord blood, amniotic fluid, and in essentially all adult organs or tissues, including bone marrow, fat, kidney, liver, pancreases, intestines, breast, lung, etc. Any of these non-embryonic stem cells have ample plasticity and can give rise to nearly any type of cells, including heart, liver, lung, muscle, etc.
Thus, the heart of the stem-cell controversy centers on the aforementioned fact that the extraction of stem cells from 5- to 12-day embryos kills the embryo. But that’s not the only issue: In addition, stem cells derived from an embryonic human may, in turn, reject the person who receives them. This situation is called graft-versus-host-disease (GVHD). The problem can be avoided by producing an embryonic clone of the person needing the stem cells. However, the procedure produces an embryo that is indistinguishable from an embryo from a fertilized egg. This embryonic clone would be destroyed during the stem-cell harvesting required by the therapy. This type of cloning is called “therapeutic cloning,” since the production of a human baby is not the goal. (Reproductive cloning, producing a cloned human baby, has been universally outlawed.)
Another problem is that the embryonic stem cells can unpredictably cause cancer in the treated patient.
On the other hand, newly developed treatments associated with non-embryonic (adult) stem cells are way ahead of any hoped-for treatments associated with embryonic stem cells. Recent non-embryonic stem-cell therapies include treatments for non-healing bone breaks, healing damaged hearts, regenerating damaged muscles, correcting scoliosis, regenerating knee cartilage, treating thalassemia, osteoarthritis, diabetes, lupus, multiple sclerosis, spinal chord and nerve damage. Treatments to heal conditions associated with almost any organ or tissue are in view. These advances cast serious doubt on the need to develop embryonic stem-cell therapies, especially since embryonic technologies are morally objectionable, given that they require the death of the human embryo.
The use of one’s own adult stem cells (autologous stem-cell transplant) is a way to avoid the problems of rejection and of killing human embryos. Also, certain types of adult stem cells (mesenchymal cells) can be harvested from anyone and changed in the lab (transdifferentiated) into a desired cell. In both of these stem-cell applications there are no adverse effects to the donor of the adult stem cells. The non-embryonic stem cells are safely harvested, purified from other cells and/or expanded in culture, and introduced into the patient without rejection. In another process, virtually any adult cell can be harvested from one’s own body and treated to become cells capable of producing the needed cell type (induced pluripotent stem cells or iPS). These cells can also be cultured in the lab, and reintroduced into the patient. All of these sources of adult stem cells avoid the problem of having to use patented embryonic stem-cell lines that would be less available to the public.
And yet, the reputed plasticity of the embryonic stem cells continues to make the prospects of doing research on human embryos attractive to researchers who are uninhibited by the prospect of killing human embryos.
It is worth pointing out that, in terms of medical applications and treatments, two major facts are usually left out of these discussions: First, non-embryonic stem-cell treatments have been used to treat tens of thousands of patients, and with dramatic benefits. However, embryonic stem cells have not had one clinical trial with humans. Also, it has been clearly demonstrated that non-embryonic stem cells do not produce cancerous tumors in humans. Whether iPS cells share this non-tumorigenic quality is not yet clear. However, iPS cells have all of the medical application value hoped for in embryonic stem cells.
It must be noted that in a field as rapidly moving as stem-cell research, this situation will likely not be current for long. However, the current progress of stem-cell research as of spring 2009 speaks volumes regarding the effectiveness of non-embryonic vs. embryonic stem-cell research. The promises of embryonic stem-cell researchers are wildly overstated. The claims that embryonic stem-cell therapies will be available in five to 10 years rings hollow.
Aside from these scientific considerations, there are moral-religious matters of obvious concerns to Christians:
Christians committed to the sanctity of human life should look with favor on technologies that preserve and/or improve human life. Consequently, non-embryonic stem-cell advances should be embraced when they: 1) respect the consent and preserve the dignity of the stem-cell donors, 2) enhance the health of the stem-cell recipient, and 3) protect human life at every stage of development. Embryonic stem-cell harvesting remains problematic because the procedure destroys the smallest and most helpless members of the human family: embryos.
In truth, embryonic stem-cell use is being trumped by successful and surprising advances in adult and other non-embryonic stem-cell research. These advances protect the dignity of the donor and recipient while recognizing the value of all humans, regardless of their stage of life, from conception through old age. Hence, all frozen human embryos should be given a chance to be born, not given over to researchers to be destroyed for the sake of a research project.
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- Crucial Differences Between Non-Embryonic and Embryonic Stem Cells - July 10, 2009